In the straightening of automobile and vehicle bodies for the repair of wrecked or damaged ones, it is the practice to stretch the bodies back to their original shapes. Many and perhaps most of the automobiles built at this time are of "unibody" construction. In this construction the body acts as the frame to which all of the other components are attached. This is in contrast to previous constructions where vehicles were built on a lateral frame having the components and the body attached thereto. With the present construction it is not possible to straighten the frame and repair the various components while detached from the frame.
In the repair of unibody constructed automobiles, with the body being the frame, it is necessary to bring the body back to it original shape and this is done by pulling the body from various points either simultaneously or singularly. Naturally, very high forces are involved and the present day "body shop" is equipped with various devices capable of bringing these forces to bear at appropriate positions around and on the body.
Practitioners in this field have patented various devices to carry out the purposes described above and these are represented by example in U.S. Pat. No. 4,510,790 Hare. Other examples will be seen in the advertisements found in the Trade Journal "Automotive Body Repair News". The January 1990 issue is cited as an example thereof.
An example of a commonly used pulling device is shown in U.S. Pat. No. 3,108,629 Jenkins in FIG. 1. The device shown therein is commonly called a "Dozer". Probably more body shops use a Dozer in one form or another, in contrast to the more complicated frame machines that are used in the Hare patent and the advertisements of the Trade Journal cited above.
It is also a common practice to provide anchors in the concrete floor of the shop to attach holding chains between some portion of the body and the anchor. At some point in the "stretching" system hydraulic cylinders are provided to exert the forces necessary to stretch the body back to its original shape.
As an adjunct to these systems it is necessary to grip the body at the various points where the forces are to be exerted.
Getting a firm grip on the body sufficient to withstand these high pulling forces is a difficult problem. Various practitioners have provided devices for this purpose.
U.S. Pat. No. 4,770,025 Graf discloses a frame clamp with adjustable jaws, and a bolt with nut.
U.S. Pat. No. 4,519,236 Celette reveals a clamping device which clamps the frame between jaw components 24 and 25.
U.S. Pat. No. 4,248,078 Russo describes an apparatus for clamping a rocker panel and seam section of a unitized automobile body. Bolts and nuts are used.
U.S. Pat. No. 3,955,249 Shiozaki discloses a frame clamp which closes when a wedge is pulled into rocking clamp jaws.
U.S. Pat. No. 3,631,705 McCaffery reveals a device to insert and anchor a wedge clamp bolt in a "blind" box frame. The bolt includes a nut.
U.S. Pat. No. 3,108,629 Jenkins shows a body frame clamp having bolts that are threadedly passed through one side of the clamp to engage and force a frame member against an indent on the other side.
These prior art approaches have not completely satisfied conditions that exist in this practice.
For this reason many practitioners follow the practice of bolting or welding an attachment plate to the body at the position where the pull is to take place. If welding is the method used then the weld, of course, must be removed and this often requires taking out a piece of the frame which must then be replaced with additional welded pieces. This is time consuming and complicated.
If the bolting method is used the common practice is to provide a pull bar having holes therein. The pull bar is placed against the frame and holes matching the pull bar are drilled through the frame. Following this, bolts are placed through the holes and nuts are placed on the opposite side. Placing the nuts on the bolts is very difficult and often very time consuming. There is little space to place the nuts and they are often in places where other parts make it impossible to see the ends of the bolts for the threading process.
This invention is an improvement on the bolting method by providing a series of clamping bars to form a set of tools capable of being used by one person for attachment to the frame.
In the previous method it is necessary that two persons take part in the bolt clamping process. This is because there are three parts to the process i.e., the bolts, the plates, and the nuts requiring three hands. One of the objects of this invention is to provide a system capable of being operated by one person therefore providing time savings and reducing complications of scheduling in the set up operations.